The present invention is directed to a rock drill with an axially extending shank and a drill head on one end of the shank with a drill face on the drill head directed in the drilling direction.
Rock drills are used for cutting boreholes in rock, concrete, masonry and the like and the boreholes serve for receiving fastening elements, for the passage of pipes and cables as well as for blasting. Up to the present time, two different types of rock drills using hard metal inserts have been known.
Rock drills with one or more cutting plates or inserts are relatively easy to produce and basically are used in cutting small diameter boreholes up to a diameter of approximately 35 mm. Such drills, however, have the disadvantage that the cutting edges of the cutting inserts, particularly in the radially outer region, wear out rapidly whereby the progress of the drilling operation rapidly decreases. Furthermore, handling of the rock drills is impaired due to the corner wear.
In particular, in larger diameter drills, as is known from the German OS No. 2 528 003, the drill face of the drill head is provided with hard metal cutting pins. Such cutting pins exert high pressure on the material being cut due to the small contact faces and, as a result, afford better drilling progress. Unlike cutting plates, individual cutting pins are expensive to sharpen. Furthermore, in a drill using cutting pins, the centering of the bore during the initial cutting operation is ineffective. If the individual cutting pins become damaged or broken, the rock drill becomes useless, since in practice the pins cannot be replaced.